Two slit interference on 1024×1024 lattice

Boundary conditions

Textures with simple and natural periodic boundaries are used in previous
applications (corresponding to periodic grid of fictitious sources).
To take into consideration complex boundary it is enough to "draw"
corresponding region carefully. Then the boundary values will stay fixed
during calculations. The pattern shown to the left is used to simulate two
slit interference. Here a = 1 - 2/N, N = 1024.
Corresponding texture coordinates are calculated as
Tk = (Rk + 1)/2.